3D printed electric longboard

29-06-2017

This project started when Joris Helming shared his idea of converting his longboard to an electric longboard. I’ve done several projects with Joris in the past (Mixblocks, Virtual Supermarket, VR Eye tracking hardware) and spent countless hours skateboarding as a kid and still use a skateboard as a means of transportation, so I was interested to see if we could pull this off.

Without going into detail, let’s first have a look at the results! This is us going for a test drive:

And some pictures of the final product:

During our tests we found that the maximum speed is 32 km/h and it has an action radius of about 10km with our battery pack (2x4S lipo). Or 8km if you want to outpace electric bikes.

Read more about the development process below!

Background & goal

With several players on the market (like Boosted, Evolve and Inboard) why bother to do it yourself? Well, for those who already own a longboard or skateboard like us, a $1200 to $1500 price tag is a bit high. So we wanted to see if we could develop an affordable DIY-kit, without requiring any technical knowledge or special tools/equipment to mount on an existing board.

The development process

Now that I’ve showed you the results, it’s hard to imagine how many hours went into this project. I’ll try to summarise the development phases:

Analysis phase

An electric skateboard/longboard relies on a combination of components:

Motor: a brushless outrunner motor, to be precise. These have a high torque at low rotation speeds. This is a fairly exotic part, since it needs to be 200-300 Kv motor (250-300 rotations per minute per Volt). Commonly available outrunner motors are rated higher than that (at the time of writing).

Battery pack: luckily, lithium polymer (Lipo) batteries are commonly available now. An important spec here is the C-rating, which determines the maximum discharge rate.

Mounting bracket: the part to which the motor is attached.

Gearbox - consisting of a timing belt and 2 gears: the transmission of power between the motor and the wheels.

Housing: keeps all components together and protects you and your shoe laces from the motor (an outrunner motor spins on the outside).

Idea phase

We didn’t spend a lot of time in the idea phase for this project, since we already had a good idea of what we wanted to build and wanted to get to the prototyping phase as soon as possible. But we did take some time to ask ourselves “So, let’s assume we’ve built an electric longboard - and then what?”. Here, we went through various scenarios and came to the conclusion that we wanted to evaluate 2 options:

A DIY kit - providing ready-to-assemble kits with all the components you need and mounting gear (getting the right combination of components is not easy).

A board for the Dutch market. We don’t have mountains here, but we do have separate bike lanes almost everywhere in the Netherlands. An electric longboard makes a great option for commuting.

Concept phase

We decided to pursue the DIY kit route first to scratch our own itch. The specifications of all the components greatly influence the performance of the electric board and there’s an interplay between these components. So in this phase we calculated what kind of components we would need for our own kit:

And we designed the 3D parts:

Prototype phase

This is our first prototype test with the remote controller and the motor assembly attached to the longboard. Since all the parts that hold it together are 3D printed (on a Zortrax M200 with Z-ULTRAT material) we wanted to make sure it’s stable and secure. Just to give you an idea, this is a 2,3 horsepower / 1680W / 300Kv motor. Honestly we didn’t expect it to be this stable for a plastic prototype. Truth be told, we have broken at least 10 parts and wasted 100+ 3D printing hours before we got the parts strong enough.

Why we stopped after the prototype

In short, here are the main reasons why we didn’t put any more effort in making a product out of this prototype:

We were able to design the mounting hardware for our own board, but the hassle of making it universally applicable outweighs the business potential in our view.

We found that the Netherlands Vehicle Authority (RDW) currently prohibits the use of electronic boards in public. There are some serious liability issues in case of an accident because it’s a motorised vehicle. That shouldn’t be a problem for a true DIYer, but it’s not the type of discussions we want to get into when starting a new business.

After all, we have our own DIY electric longboard now. Mission accomplished :-)

Stefan.Lu / Stefan Lugtigheid

I'm a freelance product developer. I help startups and innovative companies by developing new products/services with them. I specialise in translating abstract ideas into concrete solutions through a systematic design process.

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